Purpose: :
Previously we reported that early correction of strabismusis important in preserving the disparity sensitivity of neuronsin the primary visual cortex (V1) of infant monkeys (Mori etal, IOVS, 2002). Because normal disparity sensitivity of neuronsin the early stages of cortical processing is a fundamentalrequirement for alignment, fusion, and stereopsis, we systematicallyinvestigated how the age of surgical correction in strabismicpatients influences the degree of fusion, later alignment andprevalence of stereopsis. Because the stability of fixationand alignment of infants that receive surgical corrections isknown to exhibit considerable changes over time, we systematicallyobserved our subjects over a period of 10 years.

Methods: :
Seventeen cases of early strabismus were analyzed. Theage at which surgical and/or optical corrections were made rangedbetween 10 months and 6 years. Cover test (APCT) was used toassess alignment and Titmus stereo–tests were employedto assess stereopsis in addition to photographic examinationsof alignment. Fusion was examined with Synoptophore test. Theoverall evaluation of surgical success was done using a traditionalvon Noorden approach of dividing the subjects into 4 categories,i.e., ideal, satisfactory, acceptable, and unsatisfactory.

Results: :
The best results for fusion, alignment, stereopsisand overall success were obtained in two subjects that receivedsurgical correction of esotropia at 10 and 11 months of age.The worst results were obtained in two subjects that receivedsurgical corrections after 4 years of age. The mixed resultswere obtained in the group in which surgical corrections weremade between 1 and 4 years of age (n = 13), but the outcomewas generally better when corrections were made within 2 yearsof age.

Conclusions: :
Our results generally agree with the clinical opinionthat surgical and/or optical corrections of infantile strabismusshould be made at the earliest possible age following the detectionof misalignment to preserve fusion, stereopsis, and/or lateralignment.